The present invention relates to a germ removal or sterilization treatment of microorganisms such as viruses included in rivers, water for beverage use or water (such water to be treated will hereinafter be referred to as the for-treatment water) for use in a pool, public bath, hot spring or the like, and it also relates to a water treatment device for removing a scale.
In recent years, a water treatment technology for removing microorganisms such as bacteria, mold and protozoa included in rivers, water for beverage use, or water (for-treatment water) for use in public bath, hot spring or the like has rapidly developed.
As one of such water treatment devices, the applicant has previously developed a device including a pair of electrodes and a conductor capable of trapping the microorganisms in the channel of the for-treatment water, whereby a positive charge is applied to this conductor, and a negative charge is applied to the electrodes, to allow the conductor to adsorb the microorganisms (e.g., see Patent Document 1: Japanese Patent Application Laid-Open No. 2005-254118).
The water treatment device of the above patent document can treat the microorganisms in the for-treatment water without using any reagent such as chlorine or ozone, which produces effects that the generation of odor peculiar to chlorine or ozone can be avoided and that an intricate operation for introducing the reagent and danger during handling can be avoided.
However, in the above water treatment device, the microorganisms can be adsorbed and removed, but the density of the current applied to the electrode is low. Therefore, the microorganisms cannot be destroyed using electric shock or hypochlorous acid, and the conductor periodically needs to be taken out to remove the microorganism adsorbed by the conductor with the reagent or the like, so that maintenance and management are laborious.
Moreover, in a case where it is considered that a greater part of the microorganisms in the for-treatment water is adsorbed and removed, the for-treatment water is passed through such a device many times. Alternatively, when the for-treatment water is passed once (one water passage) and treated, the water has to be passed at such a very low flow rate to such an extent that any force stronger than a coulomb force generated in the microorganisms is not generated. Thus, there has been a problem that a treatment efficiency is very low. This is because the surface of the conductor is not flat, and is therefore non-uniformly charged to lower a microorganism adsorption efficiency. Furthermore, the conductor is not sufficiently brought into close contact with a first electrode that energizes this conductor, so that a contact resistance between the conductor and the first electrode for the energization increases, and a current efficiency lowers.